In various medical applications catheters with three or more lumens are needed to deliver and/or withdraw fluid from the patients' circulatory system. For example, the physician may need to divert blood from the circulatory system through a first lumen in the catheter and at the same time reintroduce the removed blood back into the circulatory system through a second lumen. A third lumen in the catheter may be used to introduce medications and/or nutrition supplements. In another example, each of the lumens within a multi-lumen catheter may be used to introduce a different drug into a patient's circulatory system. The use of separate lumens for each drug may prevent premature mixing of the medications.
One common application of a triple lumen catheter is the use of the catheter for apheresis and for delivery of medications during chemotherapy treatment of a cancer patient. Apheresis is a process that involves the removal of whole blood in a dialysis-like fashion. In this process, blood is circulated continuously from the patient to an instrument that acts as a centrifuge or filter, allowing for the separation of specific blood parts. The processed blood is re-circulated back into the patient's body. For example, apheresis may be utilized to separate out stem cells from the blood prior to chemotherapy treatments. This is generally accomplished by hormonally stimulating the production of bone marrow to produce a high number of stem cells. The stem cells are separated from the rest of the blood parts using the triple lumen apheresis catheter. Chemotherapy drugs are then administered using a third lumen in the catheter. After a given length of Chemotherapy treatment time, the stem cells are infused back into the patient's circulatory system.
To allow these blood draws and infusions, a good access to the blood stream in a large vein may be desirable. For example, the triple lumen catheter may be inserted into the patient's subclavian vein that runs behind the clavicle to establish a central line. The proximal end of the catheter may be tunneled under the skin for 2-4 inches to emerge from the chest close to the nipple. The triple lumen catheter may be used for the collection of stem cells and for support of the patient during therapy. In addition to the chemotherapy agent, antibiotics, anti-nausea medications, blood products, and fluids may also be infused through the implanted catheter.
Examples of various multi-lumen catheters are disclosed in U.S. Pat. No. 4,894,057, titled “FLOW ENHANCED MULTI-LUMEN VENOUS CATHETER DEVICE” issued to Howes, dated Jan. 16, 1990; U.S. Pat. No. 5,221,255, titled “REINFORCED MULTIPLE LUMEN CATHETER” issued to Mahurkar et al., dated Jun. 22, 1993; U.S. Pat. No. 5,378,230, titled “TRIPLE-LUMEN CRITICAL CARE CATHETER” issued to Mahurkar, dated Jan. 3, 1995; U.S. Pat. No. 5,395,316, titled “TRIPLE LUMEN CATHETER” issued to Martin, dated Mar. 7, 1995; U.S. Pat. No. 5,399,168, titled “IMPLANTABLE PLURAL FLUID CAVITY PORT” issued to Wadsworth, Jr. et al., dated Mar. 21, 1995; U.S. Pat. No. 5,451,206, titled “TRIPLE LUMEN CATHETER” issued to Young, dated Sep. 19, 1995; U.S. Pat. No. 5,486,159, titled “MULTIPLE-LUMEN CATHETER” issued to Mahurkar, dated Jan. 23, 1996; each of which is incorporated herein by reference in its entirety.
Due to design constraints, such as dimension/size limitations for insertion into a blood vessel, maintenance of structural integrity during aspiration of blood, etc., a typical multi-lumen catheter tends to possess one or more of the following undesirable properties: high recirculation of blood, low flow rate for blood circulation and medication delivery, high phlebitis, and high tendency for aspirating lumen to suck against the vessel wall. These properties limit the catheter's efficiency in blood circulation and medication delivery, which could minimize the effectiveness of the medical intervention.
Thus, an improved multi-lumen catheter with high blood circulation efficiency and high throughput for medication delivery is desirable. The improved design may incorporate one or more of the following performance characteristics: low recirculation of blood, high flow rates of blood and medications, high flow volume of blood and medications, low phlebitis, delivery of infusates in separate lumens, no dead end openings, limited sucking against vessel wall during aspiration, durable catheter structural design, capable of being produced in high volume, low production cost, capable of being placed over a guide-wire and/or a tunneler, and attractive appearance.